Covalent network crystals usually have the highest melting points and boiling points.
1st one I think.........................
Explanation:
To get a better understanding of the answer,let's take use of Fajan's rule which says that no bond is neither purely covalent or purely ionic.
For ionic compounds MP and BP are higher than covalent compounds. So in order to find the one with higher MP,it's enough to find the most ionic compound among the given options.
In LiF,LiCl,LiBr and LiI,The cation is same and anion only differs.According to Fajans rule Smaller anion and larger cation favours ionic bonding and vice versa. Since Fluoride is the smallest anion,LiF is the most ionic compound and hence it is the one with highest MP from the options.Hope it helps
Answer:
The correct option is the second option
Explanation:
Generally, the aim of science is to understand a particular concept in the best and the most correct way possible; hence experiments are done and repeated to ensure an explanation is actually true about a concept or need modification.
The atomic models have also been a "beneficiary" of this process. The different atomic models are usually been improved upon as scientists leaned more. For example, the Dalton's atomic theory has been modified to a more correct atomic description; some of which are shown below
(1) Dalton's theory suggested that an atom is the smallest unit of a molecule. We know now from different experiments (by J. J Thompson and Rutherford) that atoms are not the smallest molecules and are made up of smaller particles known as protons, neutrons and electrons.
(2) Dalton's theory suggested that atoms of the same elements are alike in all aspects. The knowledge of isotopy shows this is not always the case. As atoms of the same elements (isotopes) have the same atomic number but different mass number; hence cannot be said to be the same in all aspects.
(3) Dalton's theory also suggested that when atoms react, they do so in fixed, simple whole number ratio. The knowledge of organic chemistry shows atoms do not always react in simple whole number ratios
There are several modifications to different postulations by scientists that have also occurred aside from this, hence the most correct answer is that "As scientists learned more, they modified the atomic model"
Answer:
They are placed on the periodic table based on their atomic number.
Explanation:
In the chemistry table, you can find the molecular mass and atomic number. Atomic number represents the number of the protons of an atom, and molecular mass represents the mass of the atom. The mass of an atom is made from proton and neutron. The element is made by arranging it based on the number of protons, which was the atomic number.
